The invention relates to a supporting frame of a commercial vehicle, and in particular to a longitudinal frame support having a U-shaped profile, with a longitudinally extending central web which is flanked on at least one side by at least one angled profiled leg. The profiled support is provided with at least one angled portion. The invention also provides a process for producing the same.
A known profiled support of this generic type, used as a longitudinal frame support for a heavy goods vehicle, has a central web that is vertically disposed (in the installed state), a top flange, configured as a profiled leg, and a bottom flange, which is also configured as a profiled leg. The profiled longitudinal frame support is formed by subjecting a single-piece sheet-steel plate to different pressing and bending steps. In particular in the axle region of the supporting frame for the purpose of providing sufficient space around the axle and wheels, it may be necessary for the longitudinal frame support to be provided with corresponding angled portions in the vertical or transverse direction of the vehicle.
The shaping the sheet-steel plate to give it an angled profiled support produces a high degree of material deformation and internal stressing in the region of the angled portions. If the profiled supports are subjected to relatively long-lasting alternating loading, such deformation and internal stressing may constitute starting points for cracks, which reduce the service life of the supports.
The object of the invention is to provide a profiled support (and a process for manufacturing the same) which reliably avoids internal stressing and material deformation in the region of angled portions, and provide favourable preconditions for a longer service life of the profiled supports.
This object is achieved according to the invention, by producing the central web and the at least one profiled leg as separate components and rigidly connecting them to one another, with the central web being configured in the form of a plate, and being bent correspondingly at a point which is adjacent the at least one angled portion. The at least one profiled leg is configured as a single-piece blank which is continuous over the length of the profiled support. It has a continuous flange web, which follows the at least one angled portion, and a plurality of connecting lugs which adjoin one another and are separated from one another in the region of the bends of the central web. The connecting lugs are bent at right angles to the flange web and are connected rigidly to an associated longitudinal side of the central web.
Separating the profiled support into a central web and profiled legs makes it possible to achieve angled portions without generating internal stressing and material deformation of the profiled support. According to the invention, the separate components are formed into the desired shape simply by rectilinear bending edges, which are coordinated with one another and located in different horizontal and vertical planes; thereafter, the components are joined together. The fact that the central web and profiled legs are formed as separate components also makes it possible to use different materials and/or different material thicknesses with respective components, and in particular, to use lightweight materials for the central web.
The invention is preferably suitable for longitudinal frame supports. However, the profiled support may also be designed in the form of an angled inset in an angled region of the respective longitudinal frame support. The invention provides an increased service life for the profiled support. Moreover, considerably simpler production is achieved because only readily available tools are used, only a material-cutting device and a bending device being required. This gives increased flexibility for different variations of profiled supports, in particular longitudinal frame supports.
In one configuration of the invention, the central web is provided with at least one indentation at least on a longitudinal side, and the flange web of the associated profiled leg is bent correspondingly in the region of the indentation. An associated connecting lug is coordinated with the length of the indentation, which further improves the shaping of the profiled support, without increased cost or complexity.
In a further configuration of the invention, the central web and the at least one profiled leg are produced from different materials. In this case, a lightweight material in particular (aluminium or magnesium) can be used for the central web, which is exposed mostly to shear loading during operation. The at least one profiled leg is preferably produced from a sheet-steel plate.
In a further configuration of the invention, the at least one profiled leg is connected rigidly to the central web by a plurality of fastening elements, such as rivets or screws, which are distributed over the length of the profiled support. This is a particularly reliable type of connection, which (in contrast to welded or soldered connections) avoids the build up of internal stress. Screws provide a reasonable arrangement for the profiled legs and central webs.
The object of the invention is also achieved by the manufacturing process in which, in the region of the angled portion, a planar central web is bent out of its plane in accordance with the progression of the angled portion. A profiled leg, which is continuous over the length of the profiled support and has previously been cut to size from a single-piece plate is fitted to at least one longitudinal side of the central web. A plurality of connecting lugs and a continuous flange web which follows the angled portion are formed in the process, with the connecting lugs separated from one another in the longitudinal direction of the profiled leg by incisions which are provided adjacent the bending edges of the at least one angled portion. The connecting lugs are bent at right angles to the flange web and are connected rigidly to the corresponding longitudinal side of the central web.
The process according to the invention permits extremely cost-effective production of the profiled support, since all that need be provided are sheet-metal plates for the central web and the profiled legs, which are correspondingly cut to size and shaped by means of relatively simple and cost-effective production steps such as cutting and bending. Since simple straight bending edges are formed according to the invention, generation of high internal stress in the respective components is avoided.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.